Risk of pre-eclampsia in first and subsequent pregnancies: prospective cohort study

Objective To investigate whether pre-eclampsia is more common in first pregnancies solely because fewer affected women, who presumably have a higher risk of recurrence, go on to have subsequent pregnancies

The impact of birth mode of delivery on childhood asthma and allergic diseases : a sibling study

Background: Caesarean section (CS) has been reported to increase the risk of asthma in offspring. This may be due to that infants delivered by CS are unexposed to vaginal flora, according to the ‘hygiene hypothesis’. Objective: Our aim was to investigate if CS increases risk of childhood asthma, and if the risk increase remains after adjustment for familial confounding using sibling design. Methods: A register-based cohort study with 87 500 Swedish sibling pairs was undertaken. Asthma outcome variables were collected from national health registers as diagnosis or asthma medication (ICD-10 J45-J46; ATC code R03) during the 10th or 13th year of life (year of follow-up). Mode of delivery and confounders were retrieved from the Medical Birth Register. The data were analysed both as a cohort and with sibling control analysis which adjusts for unmeasured familial confounding. Results: In the cohort analyses, there was an increased risk of asthma medication and asthma diagnosis during year of follow-up in children born with CS (adjusted ORs, 95% CI 1.13, 1.04–1.24 and 1.10, 1.03–1.18 respectively). When separating between emergency and elective CS the effect on asthma medication remained for emergency CS, but not for elective CS, while both groups had significant effects on asthma diagnosis compared with vaginal delivery. In sibling control analyses, the effect of elective CS on asthma disappeared, while similar but non-significant ORs of medication were obtained for emergency CS. Conclusions and Clinical Relevance: An increased risk of asthma medication in the group born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora. A more probable explanation should be sought in the indications for emergency CS.Swedish Research CouncilCentre for Allergy ResearchStiftelsen Frimurare-Barnhuset i StockholmALF KI/SLLPublishe

Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study

Villamor E, Dekker L, Svensson T, Cnattingius S. Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study. Paediatric and Perinatal Epidemiology 2010.We estimated the accuracy of a non-invasive, inexpensive method (the Chinese lunar calendar, CLC) to predict the sex of a baby from around the time of conception, using 2 840 755 singleton births occurring in Sweden between 1973 and 2006. Maternal lunar age and month of conception were estimated, and used to predict each baby's sex, according to a published algorithm. Kappa statistics were estimated for the actual vs. the CLC-predicted sex of the baby.Overall kappa was 0.0002 [95% CI −0.0009, 0.0014]. Accuracy was not modified by year of conception, maternal age, level of education, body mass index or parity. In a validation subset of 1000 births in which we used a website-customised algorithm to estimate lunar dates, kappa was −0.02 [95% CI −0.08, 0.04]. Simulating the misuse of the method by failing to convert Gregorian dates into lunar did not change the results. We conclude that the CLC method is no better at predicting the sex of a baby than tossing a coin and advise against painting the nursery based on this method's result.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79303/1/j.1365-3016.2010.01129.x.pd

Mortality in infants of obese mothers: is risk modified by mode of delivery?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90196/1/j.1600-0412.2011.01331.x.pd

Psychotic Illness in First-Time Mothers with No Previous Psychiatric Hospitalizations: A Population-Based Study

Unnur Valdimarsdóttir and colleagues studied the risk factors for psychiatric illness following childbirth and found that, for women who had never previously been hospitalized for a psychiatric illness, the risk of mental illness was greatly increased following childbirth